Rh()-catalysed C-H annulation of -stilbene acids with 2-diazo-1,3-diketones: facile access to 6,7-dihydrobenzofuran-4(5)-one and α-pyrone scaffolds

• Published in: Organic & biomolecular chemistry 2024-05, Vol.22 (19), p.3933-3939
• Main Authors: Galla, Mary Sravani, Kale, Nandini B, Kumawat, Akshay, Bora, Darshana, Shankaraiah, Nagula
• Format: Article
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/d4ob00151f

An efficient Rh( iii )-catalysed C-H functionalization, tandem annulation of cis -stilbene acids using 2-diazo-1,3-diketones was devised. This protocol solely afforded 6,7-dihydrobenzofuran-4(5 H )-ones using alicyclic diazocarbonyls via decarbonylation and α-pyrones with aliphatic diazo compounds. The chameleonic nature of cis -stilbene acid was observed with various diazo compounds by altering the additives. This synthetic method furnished good atom-economy and wide functional group tolerance, and also explained the use of carboxylic acids as a directing group. In addition, a mechanistic investigation of the catalysed reaction using ESI-MS, and the fluorescence properties of α-pyrones were well explored. The establishment of this protocol provides fused dihydrofurans and α-pyrones from medicinally important scaffolds like cis -stilbenes employing an acid as a directing group via C-H activation.